[WIP] Preparation for 2.0

**This PR is a WIP.** The configuration changes were made blind. They have not been tested with Vagrant yet.

There are still some TODOs to fully restore compatibility:
* Update Jenkins-Jobs: separate deployment jobs for Backend and Mobile are needed
* ARSnova Mobile POM has to be updated to allow deployment to Tomcat
* Tomcat deployment at startup has to be separated for Backend and Mobile
* Testing!